How URL Shorteners Work

TinyURL has processed over 31 billion URLs. A redirect that takes milliseconds. A pipeline that took real engineering to survive at that scale. This video walks the full architecture — the read/write asymmetry, the ID generation bottleneck, why consistent hashing doesn't solve hot keys, and what a real production outage actually looks like. Every claim traces to a named source. Sources linked below. SOURCES ─────────────────────────────────── [S1] Richman — Bitly Engineering Blog, Jan 2026 https://bitly.com/blog/scalable-secure-short-links/ [S2] O'Connor — High Scalability, Jul 2014 https://highscalability.com/bitly-lessons-learned-building-a-distributed-system-that-han/ [S3] Yoder / Rios / Ischenko — Rebrandly Blog, Mar 2025 https://www.rebrandly.com/blog/mission-critical-link-infrastructure [S4] Bitly status page — incident Apr 25 2026 https://status.bitly.com/incidents/ny5wjrbq7994 [S5] TinyURL homepage (operator-published counter) https://tinyurl.com/ [S6] TinyURL OpenAPI Specification v2.4.2 https://api.tinyurl.com/ 00:00 Cold open — 31 billion URLs 02:04 Shorten path (synchronous write) 03:16 cache HIT 03:50 cache MISS 04:35 Hot key counterfactual 05:35 Trust & Safety 06:20 Real outages — Bitly Apr 25 2026 url shortener, how url shorteners work, system design, bitly architecture, tinyurl, url shortener system design, system design interview, distributed systems, cache aside, consistent hashing, hot key problem, key generation service, base62 encoding, redis cache, system design explained, backend engineering, software engineering, scalability, database sharding, read heavy systems, async event queue, cdn, load balancer, system design for beginners, system design deep dive